My principal is dropping classes at the last minute (2 weeks before school starts) and putting me on "home room duty" without asking me to consider it.

My principal is dropping classes at the last minute (2 weeks before school starts) and putting me on "home room duty" without asking me to consider it. I'm being told that I can't teach certain classes because I don't have a certification in them. I would have to go back to school to teach anything other than what I have a certification in. I was told that 2 weeks before school starts and now I only have 2 classes and have a great deal of free time. School doesn't start for 2 weeks so I've been assigned "home room duty." I've been told that it's mandatory and I have no say or option to get out of it. I've been told that that's the way my school handled the problem of emancipated students who don't have any morning supervision before school starts. I've been told that I have to pay out of pocket for any supplies that I need to do home room duty which includes pens and paper. I'll be paid $500 for the morning home room duty and no more. I have to be dedicated to home room duty and if I don't show up for home room duty, I'll be written up and threatened with being fired. I'm a probationary teacher and I need the job. <br><br>Does anyone have any advice on how to deal with the situation?